I have tried to implement this but the generated sql-statement hasn't brought the right result=2E The sub query wasn't right, so the values which were presented were wrong=2E The join which I have created in FM are ignored=2E My problem is, that I want to count the number of records from a detail table and add the value to the main tabular model=2E How can i achieve this?

In C8:
1 Create the Child Query
2 Create the parent Query
3 Create a filter on the parent query that references the child query (all queryies are exposed as a tab on the insertable objects pane of the expression editor)
hint: use an in clause